I am thinking of collecting Super Famicon/SNES games but one thing holding me back is the integrity of the cartridges.
There must be two grades to the collecting: (1) collecting original hardware and (2) collecting original hardware which functions.
How long will the console itself last before it is beyond repair?
As you already said it is mostly impossible to project how long real hardware will live without any failures. However you have two ways to guide you:
- Warranty period - when manufacturer guarantees you the operation of the device, and will perform replacements to return the device into working condition. This must not be applicable to the devices you are going to collect as their warranty must be void many years ago;
- Useful life of the (whole) device. You may be able to find such information in the marketing booklets, but you must understand it is marketing term, and has nothing to do with guarantees from manufacturer;
- Trying to identify cumulative MTBF (mean time between failures) for each component, and somehow mathematically estimate MTFB for whole device using probability theory. For example, 27C512 EPROM is said to retain data for more than 200 years.
Anyway, the applicable ways 2 and 3 above are assessments, and you must be ready that hardware fails sometimes. Old one as well as new one.
But the good thing is that if you store devices in proper conditions, and you have checked they are in working condition, the probability of old device being broken "by itself" (from age, not from misuse) is much lower than new just manufactured and bought device.
Assume that the user can perform basic maintenance like cleaning contacts etc. and that the consoles and cartridges are stored in a typical household environment.
Absolutely correct - store in cool dry place, with minimum of dust, ideally in anti-static bags and away from the heat (sun light or heating equipment).
I understand that it is impossible to give an exact number of years for the lifetime of these items, so a general ballpark figure would be acceptable. (i.e. 50 years, 100 years?)
The point of genuine hardware collection is (usually) having genuine devices, if they work or not, while should be very important, is a second question.
And repairing old hardware is an art these days, it may happen that hardware which was professionally repaired can be valued more than original from dusty shelf, because repaired and properly maintained hardware should be perceived as the one potentially living for another 100 years :)
PS. Last, but not least - there may be some components which degrade with the time - for example plastic cases or capacitors. You may not be able to know how much they will live until broke or become unusable, thus it would be a good idea to unpack some of cartridges and at least perform manual inspection, showing them to professional if in doubt.